Method and apparatus for indicating variations in the proportions. of a gas mixture



Feh. 3925- 1,527,721

M. WELLEY L. METHOD AND APPARATUS FOR INDICATING VARIATIONS IN THE PROPORTIONS OF A GAS MIXTURE Filed Oct. 13, 1920 Inventor: Leland M.W5HE

. Schenectady, in the county of Patented Feb. 24 1925.

UNITED STATES PATENT OFFICE.

LELAND M. WILLEY, OF SCHI QNECTADY, NEW YORK, ASSIGNbR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

METHOD AND APPARATU$ FOR INDICATING VARIATIONS IN OF A GAS MIXTURE.

THE PROPORTIONS.

Application filed October 13, 1820. Serial No. 416,735.

To all whom it'may concern: I

' Be it known that I, LELAND M. WILLEY, a citizen of the United-States, residing at Schenectady, State of New York, have invented certain new and useful Improvements in Methods and Apparatus for Indicating Variations in the Proportions of. a Gas Mixture,'of which the following is a specification.

The 'present invention relates to the determining of variations in'the proportions of a gas mixture and has for its ob ect to provide an improved method and apparatus for this purpose.

One application of my invention is in connection with boilers for analyzing flue gas to determine or indicate variations in the percentage of CO vtherein and in the following specification I have particularly described such application. It will be understood, however, that my invention is not necessarily limited thereto, but may be used wherever found applicable. I

As is well known in connection with firing boilers when the burning of the fuel in the furnace is complete,'the flue gas comprises principally CO N and 0 there being little 0 if the correct amount of air is being supplied. On the other hand, when there is incomplete combustion, CU gas will, be formed and there will be less CO gas present. In case, however, too nuichair is being supplied to the furnace, then the amount of free oxygen increases and the percentage of CO decreases. The percentage of CO pres' ent in the flue gas is indicative therefore of how completely and etiiciently combustion is being carried out in the furnace, at decrease in the pegcentage ofi CO -indicatin either incomplete combustion or an excess 0 air.

My invention is based on the fact that flue gas is about 1.06 to l.09 as heavy as air varying according to the percentage of the constituent gases and to the fact that the molecular weight of Ct) is substantially v greater than that of either, 0,, N or CO.

In analyzing flue gases according to my invention, I pass flue gass and air up through two long pipes under identical conditions of temperature and humidity, and since flue gas is heavier than air, the halo metric pressure will be slightly.greater in the flue gas pipe than in the air pipe. With the percentage of ()0 in the flue gas which indicates etiicient combustion, i. e. complete combustion but no excess of 0 the barometric pressure of the flue as will be a certain amount greater than that of the {air and with any variations from this percentage of CO gas, the difference in barometric pres sure will decrease. By measuring the difference in pressure between the two pipes therefore, I can determine variations in the percentage of C0 in the flue gas. a

In the drawing, the figure is a diagrammatic view of an apparatus embodying my invention and by means of which my method may be carried out.

Referring to the drawing, 1 and 2 indicate two vertical pipes' They may be, for example, any feet or more high, being made preferabl as high, as possible. They are open at tieir tops and at their bott me are connected to a suitable design of di erential pressure gauge 3 provided with a pointer 4 which moves over a scale 5. At 6 1s a suitable motor driving two synchronous as pumps 7 and 8. Pump 7 has its suction side connected by a pipe 9 to an air washer and humidifier l0, and its discharge side connected by pipe 11 to pipe 1. Pump 8 has its suction side connecte by a pipe 12 to a gas washer and humidifier l3 and its discharge side connected by a pipe 14 to gas pipe 2.

In operation, pipe 15 is open to' atmos-' phere and pipe 16 is connected to the furnace at a suitable sample of the flue gas for analysis. Motor 6 operates pumps 7 and 8 in synchronisin, and these deliver air and as respectively to pipes l and 2 under exact y the same conditions-as to pressure. As a result, there is a steady {low of air and gas up the two pipes.

The air is subjectedto exactly the saine treatment as the flue gas so that when fed up pipes i. and 2 both will be under the same (lllllll'lOllS as regards temperature and humidity. If found desirable I may entwine pipes 1. and as shown inthe drawing to assist in maintaining similar temperature conditions in both pipes. Q

As will be clear, if air were supplied to point for extracting a for.

both pipes land 2, then the barometric presgauge 3 would be the same and the indicating needle would point to zero on the scale. If, however, flue gas is supplied to pipe 2 then its greater baron'ietric pressure will cause a deflection of the indicating needle toward the right, as indicated in dotted lines. \Vith a certain percentage of CO in the flue gas, the percentage desired for most.

efficient combustion, for example, the flue gas will have a barometric pressure a certain amount greater than that of the air and the indicating pointer Will stand in a certain position. When inefticientcombustion is taking place such as would occur, for example, by the supplying of either too much or too little air-to the furnace,-then the percentage of CO in the flue gas will decrease with the result that the barometric pressure in the flue gas pipe 52 will decrease and the pointer 0f the dii'l'erential pressure gauge move toward the left. This will indicate to the operator that combustion is being inefliciently carried 011,:and he will thereupon correct the firing of the boiler to bring the pointer back to the position indicating the correct percentage of C0 The scale 5 may be calibrated in either percent elliciency of boiler or per centCO and could be either indicat ing or recording as found desirable.

' As is obvious, the principle embodied in my invention can be carried out in conneetionwith any gaseous n'nxture tor indicating variations in their respective propor- I tions in any case where the molecularv weight from that of the other, and while I have more particularly described my invention as being utilized as a C0 indicator for flue gases, it is to be understood that it is not necessaril limited thereto.

What claim as new and desire to secure by Letters Patent of the United States, is t- 1. The method of determining variations in the amount of CO in flue gas which comprises passing flue gas and air up two long vertical pipes under the same conditions as to temperature and humidity to establish vertical columns in the pipes, and observing the relative pressures at the bases-of the vertical columns.

2. In an apparatus for indicating variat'ions in the proportions of a mixture such as variations in the amount of CO in flue gas, the combination of a difl'erential pressure gauge, two vertical pipes connected thereto, andsynchronized pumps for passing gases up said-pipes. A

of one of the gases of the mixture differs-'3 In an apparatus for indicating variations in the proportions of a gas mixture such as variations in the amount of CO in flue gas, the comb nation of a. ditferential pressure gauge, two entwined vertically ex tending pipes connected thereto, and means for effecting a flow of gases up saidpipes.

In--...\ vitness whereofll have hereunto set my handthis 11th day of ()ctober, l920.

' LELAND M. WILLEY. 

